Primary stage of two-stage hydraulic distributor



p 1962 R. LUCIEN 3,054,416

PRIMARY STAGE OF TWO-STAGE HYDRAULIC DISTRIBUTOR Filed Feb. 23, 1961 4 Sheets-Sheet l INVENTOR RENE LUC/EN 3,054,416 PRIMARY STAGE OF TWO-STAGE HYDRAULIC DISTRIBUTOR Filed Feb. 23, 1961 R. LUCIEN Sept. 18, 1962 4 Sheets-Sheet 2 RENE LUCIE N Sept. 18, 1962 R. LUCIEN 3,054,416

PRIMARY STAGE OF TWO-STAGE HYDRAULIC DISTRIBUTOR Filed Feb. 23, 1961 4 Sheets-Sheet 3 4 c .ZL N a E INVENTOR RE NE LUC/E N R. LUCIEN PRIMARY STAGE OF TWO-STAGE HYDRAULIC DISTRIBUTOR Filed Feb. 25, 1961 4 Sheets-Sheet 4 INVENTOR REN LUC/EN 3,054,416 PRIMARY STAGE OF TWO-STAGE HYDRAULIC DISTRIBUTOR Ren Lucien, Neuilly-sur-Seine, France, assignor to Recherches Etudes Production R.E.P., Paris, France,

a corporation of France Filed Feb. 23, 1961, Ser. No. 91,151 Claims priority, application France Mar. 2, 1960 8 Claims. (Cl. 137--82) The present invention relates to an improved primary stage of a two-stage hydraulic distributor.

More particularly, the present invention relates to a primary stage, of the type having a blade and a torsion tube.

A distributor in accordance with the invention is shown in the following figures of the accompanying drawings, given by way of example and without limitation:

FIG. 1 is a diagrammatic illustration of a first embodiment of the invention;

FIG. 2 is a portion of the embodiment in FIG. 1 shown on enlarged scale;

FIG. 3 is a perspective view with parts broken away and partial cross-sections, of the general arrangement of the distributors of the embodiment of FIG. 1;

FIG. 4 is a cross-section in plan, taken along the broken line IVIV of FIG. 5;

FIG. 5 is a cross-section in elevation, taken along the line VV of FIG. 4, or along the line V-V of FIG. 6;

FIG. 6 is a cross-section in elevation following the broken line VIVI of FIG. 4;

FIG. 7 is a diagrammatic illustration of a second embodiment of the invention;

FIG. 8 shows a portion of FIG. 7 in section and on enlarged scale.

The principle of the distributor according to the invention will be explained with reference to FIG. 1. The motor of the distributor is of the type generally known as a torque-motor, and essentially comprises a magnetic blade 1 oscillating about an axis XX in the air-gaps 2 and 3 of a magnetic circuit formed in two parts 4 and 5, polarized by a permanent magnet 6, under the effect of two windings 7 and 8 surrounding the blade 1 and receiving the control current or currents. The magnetic blade 1 is coupled to the blade 9 of the jets by a rigid shaft 10 which is the physical embodiment of the axis XX, formed in the manner indicated in detail in FIG. 2.

The rigid shaft 10 is surrounded by a cylindrical tube 11 which forms an integral part of a fixed base member 12. At the two extremities, a coupling joins together the three members, namely: a screw 13 couples together the magnetic blade 1, the rigid shaft 10 and the tube 11, while a screw 14 couples the blade 9 of the jets, the shaft 10 and the tube 11. These parts are dimensioned in such manner that the tube 11, by its two halves, constitutes a torsion bar between the fixed point 12 and each of the two blades 1 and 9, while the rigid shaft 10 couples the two blades 1 and 9 in torsion. The whole system serves at the same time as a suspension for the two blades, and also as a hermetic closure device, as will be described below.

Referring again to FIG. 1, the jet blade 9 oscillates about the axis XX between two pairs of jets 1516, 1718. The jet nozzles 15 and 17 are connected together through a piping system 19; similarly, the jet nozzles 16 and 18 are connected together through a piping system 29. Each of these piping systems 19 or 20 is connected on the one hand to a chamber 21 or 22 which actuates the slide-valve 23 of the secondary stage of the distributor, and on the other hand through a Staes atent calibrated orifice 24 or 25 to the inlet 26 of the fluid under pressure.

As the said secondary stage of the distributor does not form part of the present invention, it will not be described in further detail, but it is clear that it can be of any known type determined by considerations of choice or availability.

The members already described with reference to FIGS. 1 and 2 will again be found with the same references in FIGS. 3 to 6. In FIG 3, it can clearly be seen how the torsion tube 11 and its base 12 form the fluid-tight closure of the jet chamber 27 with respect to the chamber 28 of the magnetic system.

When a current is passed through one of the windings 7 or 8 or when these two windings 7 and 8 are traversed by different currents, an electro-magnetic torque is applied to the blade 1, which rotates on its shaft 10 in opposi tion to the elastic restoring force of the torsion tube 11. The rigid shaft 10 drives the blade 9 of the jet nozzles in rotation; the blade 9 is thus brought closer to two jet nozzles, for example 15 and 17, and moved further away from the two other jet nozzles 16 and 18 (FIG. 1). The losses of pressure in the piping system 19 and 20 are thus unbalanced, and there results a differential pressure for controlling the slide-valve 23 of the secondary stage, this pressure difference being proportional to the difference between the control currents in the windings 7 and 8 and changing sign with reversal of that difference.

From the hydraulic point of view, it is not necessary to have four jet nozzles since two would suffice, but the arrangement with four jets constitutes a hydraulic system which takes up shearing stresses liable to cause undesired bending of the elastic tube. Thus, with only two nozzles, there would be an unbalanced force on the blade 9 in a place perpendicular to the axis of the tube. This unbalanced force would act on the end of tube 10 to produce shear and bending forces on the tube. By providing four nozzles the force on blade 9 is equilibrated and shear and bending on tube 10 is obviated. A further advantage of this arrangement with four jets is its insensitivity to vibration in the event of utilization on an engine for example. In this system, in fact, since the masses are the same on each side of the shaft, longitudinal vibrations do not give rise to a driving torque (which would have the effect of a control signal and would result in a disturbance). In the same way, longitudinal vibrations in the direction perpendicular to the plane of the blades could cause a bending movement of the tube (which movement would be limited, since the tube has a high resistance to bending), and this movement would cause the hydraulic blade alternately to approach and move away from the jet nozzles, which would have the same eifect as a rotation about the axis of the tube in the case of two jet nozzles.

In the system with four jet nozzles, the associated nozzles being on each side of the blade, a transverse displacement does not cause any variation in pressure loss, since the sum of the clearances between the nozzles and the blade remains constant. Due to the use of four jet nozzles, however, the manufacture and the adjustments are more complicated than if there were employed only the two jet nozzles which are sufiicient to ensure a correct hydraulic operation.

Experience has shown that for reasons of simplification of adjustment, the arrangement with two jet nozzles may be more advantageous. In this case, according to the invention, there is added to the primary stage a mechanical device (and not hydraulic) for resisting the force developed by the nozzles in a plane perpendicular to the axis of the tube to avoid shear and bending stresses in the tube.

By way of non-limitative example, a mechanical device 3 of this kind will be described with reference to FIG. 7, which corresponds to FIG. 1 with the same reference numbers designating the same members, and to FIG. 8 which is a detail in cross-section of FIG. 7.

It is clear that the two jet nozzles 16 and 17 apply hydro-dynamic reactions to the blade 9 which are orientated in the direction of the arrows 29 and 39. In accordance with the invention, the resultant of these two reactions is taken up by a mechanical device, such for example as a thin short blade 31, coupled on the one hand to the jet blade 9 and on the other to the fixed portion 32. In addition, the invention provides that the blade 9 should be constructed in such manner that its two active faces 33 and 34, facing the jet nozzles 16 and 17 and co-operating therewith, are in a plane passing through the axis XX of the rigid shaft it), this plane being represented by the line Y-Y shown in FIG. 8.

What I claim is:

1. A primary stage for a multistage distributor comprising a torsion tube adapted for rotation about an axis, a blade on said tube, means coupled to said tube to rotate the same, a pair of parallel jet nozzles adjacent said blade and controlling said distributor in accordance with the distance of said jet nozzles to said blade, said jet nozzles being on opposite sides of said axis of rotation and lying in a plane directed perpendicularly to said axis, such that said jet nozzles apply an unbalanced force in a plane perpendicular to the axis of rotation of said tube With the jet nozzles connected to a supply of a pressure medium, said unbalanced force normally producing shear and bending forces on said tube and means operatively coupled to said tube to resist said unbalanced force in the plane thereof to prevent the application of shear and bending forces on said tube.

2. A primary stage as claimed in claim 1 wherein said nozzles are substantially perpendicular to said blade and equally spaced therefrom with the blade in a neutral 4- position, said nozzles being located on the same side of said blade.

3. A primary stage as claimed in claim 2 wherein the means resisting said unbalanced force comprises a nozzle aligned with each of the first said nozzles and on a side of the blade opposite to that of the first said nozzles.

4. A primary stage as claimed in claim 3 comprising means coupling nozzles on opposite sides of said blade and on opposite sides of said axis together for connection to a source of pressure medium.

5. A primary stage as claimed in claim 1 wherein said means for rotating the tube comprises a magnetic blade on said tube and a torque motor operatively coupled to said magnetic blade for rotating the same.

6. A primary stage as claimed in claim 5 wherein said torsion tube comprises a rigid shaft and a pair of tubes in end to end relation concentrically surrounding said rigid shaft, said blades being on different tubes and at ends remote from the adjacent ends of said tubes, means rigidly connecting said blades to the corresponding tube and to the rigid shaft, and means supporting said tubes at their adjacent ends.

7. A primary stage as claimed in claim 1 wherein said means resisting said unbalanced force comprises a thin blade perpendicular to the axis of said tube and having one end coupled to the first said blade and an opposite end which is fixedly supported with respect to said torsion tube.

8. A primary stage as claimed in claim 7 wherein said first blade has a face facing said nozzles which lies in a plane containing the axis of rotation of said torsion tube.

Binckley Oct. 13, 1931 Brandstadter :May 20, 1958 

